Posted
by
samzenpus
on Monday November 04, 2013 @05:25PM
from the imitation-is-the-sincerest-form-of-flattery dept.

The Bad Astronomer writes "A new study, looking at over 40,000 stars viewed by the Kepler spacecraft, indicates that 22% of stars like the Sun should have Earth-like planets orbiting them — planets that are similar in size to our home world and with a surface temperature hospitable for liquid water. There are some caveats (they don't include atmospheric issues like the greenhouse effect, which may reduce the overall number, or at cooler stars where there may be many more such planets) but their numbers indicate there could be several billion planets similar to Earth in the Milky Way alone."

and these aliens had thunderbolt hammer that were really nuclear weapons, and they flew around in vimanas which were really flying ships from a floating castle mothership, in order to interbreed with earth's primitive dwellers by taking human form.

I love Ancient Aliens. one of the best shows on TV. Watching them come up with their wild pseudoscience theories is like watching a monkey discover how a cigarette lighter works.

The odds on this subject swing around more than back alley crap game.I doubt anyone in Vegas would have a line on it. It's that bad.What will the numbers be tomorrow? How about next week?Damn, go home and don't come back till this resembles Science.

I've often suspected that our planet was colonized by the "B" ark. There's so many indicators... The Kardashians, reality TV in general, pop music, sensationalist news, congressional press releases, the MPAA, offshore helpdesks, Snooki being on TV for any reason whatsoever, Darwin awards, the Kardashians. Pretty much confirmed, really.

An optimist - and for these purposes, I qualify - might look and think, "isn't it wonderful that the only reason any of this crap is relevant is that we have a global communications network that can transmit any information at the speed of light to billions of people?" The same optimist would probably

There's a near-zero chance that your exact genetic sequence would ever come into existence during the course of the universe as we understand it, and yet you exist. The same is true for basically everyone else, yet identical twins exist which doubly-defy the odds! You're more likely to bit struck by lightning than to jackpot a big lottery, yet those lottery winners exist too. So do people struck by lightning, as a matter of fact.

By definition, the planet we arose on is Earth-like because that's the prototype to which all other planets are compared for Earth-likeness. There is a 100% chance that the planet we arose on is Earth-like. Also, there's nearly 100% chance that the first non-Earth planet that we inhabit to the same degree that we inhabit Earth now is also Earth-like, since we'll likely aim for the Earth-like ones, since, again pretty much by definition, we are biologically adapted to live in Earth-like planets.

If the speed of light is the absolute max speed in the universe, with no shortcuts in practice, getting somewhere outside of local star group won't be ever possible, and the same will be for everyone else, no matter how advanced they are, and how much similarities are between their culture and ours (at least, our culture willingness to go to space and communicate with others). And, of course, there is time, they should be at the right stage of their civilization, of the 4.5billon years of this planet just in the last 100 we were sending and trying to hear signals to/from somewhere else, and not sure for how much time we will be around. And if well could be earth-like planets "close", sending an expedition even to the closest solar system to just plant a flag is outside our reach, maybe for centuries (and getting there and back will take even more centuries)

The universe may be full of life and advanced civilizations, and we probably won't ever know that someone else is out there. Nor them.

Exactly. We don't know what we don't know. So yes, at the moment, the best we can do is find these planets, see if we can recognize the signatures of life (the discovery of which would be monumental whether we can ever get there or not), and bequeath that information to future generations who may have far greater technical and scientific capabilities than we do.

Even if that turns out to be the case, the one thing we may develop in the future are better ways of harnessing energy. Even if the speed of light remains the limit, and no feasible way around it (ie. wormholes, warp, whatever), we could still conceivably accelerate spacecraft to a reasonably high fraction of c which would, while not helping out observers on Earth, allow voyagers, one way or the other, to reach other stars in far less time. Tens of thousands of years to the nearest possible lifebearing solar systems could be dropped to a few centuries.

So we can get there in 5-10 generations of space travelers? Just making a self contained system that can support life that long without resupply is going to be some feat. Staying alive in the harsh radiation environment of space for 200 years will be quite another. Keeping the equipment working that long will be even more unthinkable if there is any kind of complexity to the technology used.

We are stuck in this solar system, and the future does not look good. Eventually the sun will make the earth into s

If we're postulating that in the next few centuries we come up with energy sources that could accelerate us to something like 20% of c, then I'd say we probably have the tech to build the shielding. We'd have to, as moving at such a high fraction of c means radiation approaching us going to be blue shifted, and thus more intense.

But hey, if it makes you feel special to imagine we're doomed and that there is some sort of limit on the kinds of technologies that we can develop to deal with what would still remain problems of physics as we understand it now, be my guest.

What you want is a "starwisp". Accelerating meat to near-c and then trying to shield it is silly. Accelerate a 1 kg computer carrying AI instead. AI is no more of a reach than the idea of harnessing that much power, so why not?

If we're postulating that in the next few centuries we come up with energy sources that could accelerate us to something like 20% of c, then I'd say we probably have the tech to build the shielding.

I'm going to further postulate that if we somehow manage to devise such technology, we've probably also significantly extended the human lifespan, and therefore the institutional attention span, and we'll be able to start thinking about robotic precursor missions well before we start flinging people across inters

Long term low level radiation exposure is deadly to life of all kinds. The simpler the life form, the better is survives, but the more complex forms are much less resistant. Human life is one of the most complex, so it will be more easily damaged by the radiation in space. This will make it necessary to provide radiation levels close to those on earth's surface or the occupants of the craft will not survive the 100+ year one way trip.

"It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Univers

Based on what we *know* right now, our best-bet is to build a series of self-sustainable "generation ships"; (very-large spacecraft, capable of sustaining human life over the course of several generations, including the necessary ecosystems to support such life.)

Such technology is at least theoretically do-able, from a technical standpoint.

From an ECONOMIC standpoint, of course, it is as impossible as faster-than-light travel. To expend the money required for such an enterprise, to send-off one or more suc

is not something that can be done with a civilization that does not even want to invest the money to educate their own children. And this would only happen if we knew, for certain, that the destination worlds were inhabitable.

Well, I can probably come up with some scenarios that would be sufficiently motivating for a generation ship to be built - but they basically all involve imminent global catastrophe and decades of authoritarian government, central planning, and slave labor (or close to it). After all

If you have the technology to build generation ships, then you essentially have the technology to build self-replicating space habitats which can duplicate themselves using sunlight and asteroidal ores. (See JD Bernal's ideas form the 1920s or GK O'Neill's from the 1970s or MT Savage's ideas from the 1990s). WIth such technology, there woudl be enough living space for quadrillions of humans in just this one solar system.

Of course, in a thousand years or so, we may be bumping into such limits for the solar s

Unless, of course, y'know, we don't know everything there is to know about physics.

We don't know everything, but we know the broad strokes to a staggering level of accuracy. There's dark corners and more than enough details to go around for aspiring PhDs, but its just wishful thinking and imagination to believe there are major swaths of physics we're so completely and totally wrong about.

Didn't we discovee an entire newuforce (technocolor or something?) Less than 2 years ago? And do you know any detail of gravity for certain? What about dark matter and possibly the WIMPS? Supersymmetry? M-theory?

The standard model has over 50 fudge factors...its broken. What If there are particles and/or forces outside of our little sphere that would enable this?

The standard model has over 50 fudge factors...its broken. What If there are particles and/or forces outside of our little sphere that would enable this?

I don't think we've even scratched the surface yet.

You might as well claim that magical pixie dust and the hand of Jesus will push spaceships faster.

The standard model, except on quackery websites, isn't broken. There are no particles found that don't match it, and the ones it predicts get found. That's the point -- there's plenty of room to fill in details but something fundamentally breaking special relativity is not hiding in those cracks. The whole shebang is completely and totally wrong from the ground up, if so... and theories that are accurate to thi

1) What about the very real possibility of the technicolour force? Granted, that doesn't break the standard model, but it's something previously unknown, recently discovered, most likely exists, and has very odd properties. This proves there can be extremely large discoveries, even now. They have thought the exact same as you at various points in history.

2) The energy scales that we are able to experiment on are 10s of orders of magnitude less than what nature provides. The energy scales are utterly unimagi

The distances only seem insurmountable because of the limit of human life spans. If we could develop a way to extend our life span indefinitely, then taking a trip to another star might be an interesting 50,000 year vacation.

Actually, if you go fast enough, you don't need life-extension. The stuff you left behind may be 50,000 years out of reach, but you might only have experienced a couple of dozen years.

Unfortunately, we're probably at least as far from the necessary accelerations (and cushioning) as we are from the necessary life-extension techniques, so it's probably a moot point, but I value completeness.:)

I remember reading, somewhere, that if we could just reach something like 99% of the speed of light, the entire universe is only a year away, due to time dilation. I read that a long time ago, though, so it may be out of date.

Of course, I'd much rather find a way around having to accelerate, at all, like wormholes, or something. Between the acceleration time, the radiation issues, etc., there are many more problems with lightspeed, than just get

If the speed of light is the absolute max speed in the universe, with no shortcuts in practice,

You know, I have always suspected that there will be ways for people with very advanced science to get around speed of light problem. Several hundred years ago, gravity was a similar looking, insurmountable barrier, and that has proven to be be trivial to 'get around' provided you are willing to make the proper engineering choices. Gravity and relativity are still things we don't have a lot of understanding of, and there is plenty to learn about how and why they work.

If worse comes to worse, if we ever create energy sources capable of accelerating us to a reasonably large fraction of c, even if, in Earth time, visiting another solar system might tens or hundreds of thousands of years at non-relativistic speeds, the occupants of such a craft would experience time dilation, and for them it would be a much shorter ride.

There is a big difference. If the theories we know are correct, then FTL information transmission can violate causality. c isn't just a speed limit which we are "not yet able to beat", its violation would violate basic principles of our existence.

Going faster than light in a vacuum would violate causality. Going faster than light from point A to point B is trivial if you can take a shortcut. For instance, via wormhole. Light following the same path you do would still beat you, but you still get there in a reasonable amount of time.

Traveling faster than light through basic acceleration is a mathematical impossibility. Traveling faster than light by not crossing the intervening distance is still a debated topic. Also, there no 'law of causality' that I recall studying in physics.

Several hundred years ago, gravity was a similar looking, insurmountable barrier, and that has proven to be be trivial to 'get around' provided you are willing to make the proper engineering choices.

I'm not sure this is a fair comparison. Several hundred years ago, we at least had the example of birds and insects as proof that gravity was not an insurmountable obstacle. We also had plenty of experience making objects briefly shoot upwards, we just didn't know how to keep them there. As a result, it reall

What is the speed of dark energy? To go on and on about the speed of light, because we can see it seems to assume that we know something about the speed of dark energy. Assuming we know even one thing about dark energy seems a bit bold. I can only imagine our current fixation on c will sound like the ether to future physicists. Give us a few centuries and perhaps we'll be zipping around nicely (assuming we don't nucularize ourselves first)

I don't believe we need to go faster than light to get somewhere. Toss in a good fraction of that, say 20% or as little as 10% and things begin to appear a little closer. Within 16 light years there are 53 other stars. At 10% of light speed that is 160 years traveling time, and arguably we could do it now with the proper resources and political will. At 20% - not far off - that is 80 years. Now consider genetic modification or other advances in medical science to prolong human life. If we do so much as doub

I am just glad there are still some very smart people out there still working on the physics of the universe. There may very well be no way to realistically travel to far way star systems but we will never know if we claim universal understanding of everything and then just stop investigating.

If the speed of light is the absolute max speed in the universe, with no shortcuts in practice

That's a pretty big "if", though, isn't it? We aren't nearly qualified to even speculate on the answer to that question. If you consider the distances even in our own solar system, where the planets are enormous distances from each other compared with the scale we know, our experience of manned exploration goes from the Earth to the Moon, no farther. We still have a lot to learn. We'll blow ourselves up long before we learn it, but still, there's a lot we don't know.

We've recently celebrated the accomplishments of the Voyager probes. The Flight Data System computers on both Voyager spacecraft are 16-bit machines with a whopping 16KB of memory. Each spacecraft had a total of 6 computers, with a total memory of around 68KB. The CPU clock speeds are around 250KHz, although since it takes around 80 microseconds to execute an instruction, that makes around 8,000 instructions per second.

The phone in my pocket has 2GB of memory and 4 CPUs running at 1.7GHz. So my phone has around 30,000 times as much memory as Voyager, and the CPU is... well, my math isn't that good. 3.39 DMIPS/MHz is how many instructions per second for a quad-core Krait 300 1.7GHz chip again? I think it's 4.2 Brazilian times faster at Getting Stuff Done.

Anyway, we're pretty stupid around this planet. That's my point. I think I made it.

We still have a lot to learn. We'll blow ourselves up long before we learn it, but still, there's a lot we don't know.

+5 Sad But True.

Nuclear weapons have arguably kept Humanity from going to war on a global scale again since the end of WWII. However, for the rest of us the story didn't end there. The A-Bomb Club may have started out pretty exclusive but there are a whole lot more members as of 2013 and more hopefuls are hammering at the clubhouse door wanting in.

It's well known that the push now is for smaller and smaller-yield tacnukes, ultimately serving to blur the lines between nuclear and conventional weapons. This m

no signal that escape an atmosphere is ever truly lost.You just need a big enough antenna to tease out the signal.

For example. if we wanted to see if any plant withing 100 lights year has sent a tv signal in the lsat 100+ years we would need a micro-antenna ares the size of Rhode Island. And just add more micro antennas for more distance.

If the speed of light is the absolute max speed in the universe, with no shortcuts in practice, getting somewhere outside of local star group won't be ever possible, and the same will be for everyone else, no matter how advanced they are, and how much similarities are between their culture and ours (at least, our culture willingness to go to space and communicate with others).

you seem to have forgotten relativity. if you get to really close to C then you could travel millions of parsecs in what would seem like an hour. it would seem like most of your trip was spent accelerating and slowing down when really that hour took you much further than anything else. then again, you may want to put yourself into solid or suspended state to avoid issues with acceleration and you could travel slower if you wanted. interstellar and even intergalactic travel is completely possible. the o

The local group? Thinking a bit far out aren't we, that is over 17 million light years encompassing probably tens of trillions of stars. I think our own galaxy (~110,000 light years in diameter, ~300 billion stars) has more than enough to keep us busy and is not excessively outside of our reach even if light speed shortcuts are unavailable ("Randevu with Rama" gives I think a pretty reasonable advanced space travel method).

If we traveled at 10% the speed of light (fast but not requiring a breakthrough in fundamental physics), and built new exploration ships at each destination we colonize, it would only take a half a million years to colonize every single star in the Milky Way (source [wikipedia.org]). That's an absolute eyeblink in comparison to the age of our galaxy. I don't think it will be long before we can launch ships that could reproduce themselves and keep colonizing. Our children's generation will be investing serious research money in AI robotic systems that do asteroid mining, smelting and refining of ores. Once we get a workable.1c spaceship design, I'm sure we'll have robots that could build the things in space, from materials harvested in space. I don't think we're talking about some sci-fi fantasy land. I think we're talking about the foreseeable future. And all this invites the question: if we're so far along the process to colonizing the galaxy, why haven't one of the countless probable civilizations beaten us to it? Or if they had, why is there no trace of their colonies? That's at the core of the Fermi paradox.

if we're so far along the process to colonizing the galaxy, why haven't one of the countless probable civilizations beaten us to it? Or if they had, why is there no trace of their colonies? That's at the core of the Fermi paradox.

Maybe they did, and maybe we are the evidence of it? I can imagine a robotic probe that seeds DNA to hospitable worlds is possible, but that would just be the seeding of life, not any society/culture (and evolutionary pressures may well make the resulting beings look very different to the original). I see no difference to claiming life was brought to this earth by comets, space dust or alien robotic spacecraft (except plausibility, but we will never really know)

This is what I was thinking. We will evolve ourselves into machines and I guess we could always maintain DNA cultures and grow bodies if we need. I just wonder what would become of our humanity if we could do the Ghost In The Shell thing. It would mess with your mind to change bodies and basically be around indefinitely. Nothing is impossible, it's just not possible now. I can see humans as the Borg... taking over the universe like the plague we are on Earth:P

Let's suppose that we're limited to 1% of the speed of light for practical purposes. I think that's more realistic.

Now, suppose we establish self-sufficient habitats built out of planetoids and similar stuff. At some point, some group may decide to collect lots of fuel from a handy gas giant, and head on out. There's a lot of reasons why people might want to do that (although many, many more why not). So, somebody does that and moves
to a system maybe 10 light-years away. That takes a thousand years

Our (written) history goes back to 10k years ago. What make you think we will survive as a civilization as we have now (or more advanced) for a long time? You are talking about millon years from now. *IF* we don't get setbacks, we probably won't be humans in 200-500 years. But knowing what happened every time we got something that could be used as weapon, from fire to internet, including possibly damaging for all the planet like nuclear ones, The most immediate threat to our survival is in us, not in climat

Um, no. What stops anything from going faster than the speed of light is that the faster an object goes, the more massive it becomes. As it approaches a high fraction of c its mass approaches infinity. To get all the way to c would require an infinite amount of energy. Photons can move at c because they are massless. It is that requirement of infinite energy that makes c the ultimate speed limit. Nothing with mass can ever reach c.

Easy solution. Just prepare a spaceship with a catwalk, and use some of the already anorexic wannabe fashion models as astronauts, promising them they'll get themselves as cover on Vanity (or whatever).
By the time they are nearing C, their mass will be zero.
Problem solved.

What stops anything from going faster than the speed of light is that the faster an object goes, the more massive it becomes

No no no. I wish people would stop repeating this. That's not at all true. As you go faster, relative to me, your clock (as I see it) slows down. That's it. That's the effect of relativity. Mass is just wrong, it's all time.

The better way to explain the speed limit though has nothing to do with that. Everything in the universe goes at the same speed - c- all the time. Usually we move in the direction we call "the future" at this speed - one second per second. All any form of acceleration does is ch

What cracks me up is that not twenty years ago, I had a long discussion with a physics teacher who must not have listened to his own material and kept on arguing that we were probably the only star with a planetary system.

I remember being very small but already a scifi fanatic, and my (single at the time) mother who had been taking some college courses remarked once, appropos of nothing much, that stars were little bits of fire that weren't that far away.

I asked her where she had heard that. She said in one of her college courses.

After a long while, I asked "are you sure it was a science course?"

It was a few years later that I got around to reading Orwell, and understanding that she was probably misremembering a discussion

The vast number of potential exoplanets could never be detected by Kepler. Kepler worked by detecting occultations, and the chances of a planet at 1AU distance actually occulting a G0 star 10+ LY away would be... miniscule. Think about how few visible stars happen to be ON the ecliptic as viewed from Earth; Those would be the ONLY aliens with a Kepler-analog telescope which might discover US.

The fact that the Kepler telescope discovered as many exoplanets as it did, given the geometric odds against it,